https://leetcode.cn/problems/search-insert-position/description/
class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int left=0,right=nums.size()-1;
        while(left<=right)
        {
            int mid=left+(right-left)/2;
            if(target>nums[mid])
                left=mid+1;
            else if(target<nums[mid])
                right=mid-1;
            else
                return mid;
        }
        return left;
    }
};